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Re: ISSUE-126 (Revisit Datatypes): A proposal for resolution

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Tue, 1 Jul 2008 14:56:47 -0400
Message-Id: <0A89D05C-B3A2-4960-8458-5E9D42685AED@gmail.com>
Cc: "'Michael Smith'" <msmith@clarkparsia.com>, "'OWL Working Group WG'" <public-owl-wg@w3.org>
To: "Boris Motik" <boris.motik@comlab.ox.ac.uk>
You miss the point. It wouldn't be put there intentionally in the  
sense you have it. Rather, one would write a script that packages up  
some experimental results, output from some computation. Some of  
those values might be NaNs. I write such generating scripts (not  
usually on number at the moment) quite often.

On Jul 1, 2008, at 1:59 PM, Boris Motik wrote:

> Hello,
>
> XML Schema has already departed from the IEEE recommendation  
> because they donít have +0 and -0. These constants are used to  
> express problems arising while evaluating numeric operations; for  
> example, dividing 1 with 0 returns NaN.
>
> How many OWL 2 ontologies containing NaN (that are not a test case)  
> are there?

None, because there are no OWL 2 ontologies yet.

Ask again a year after OWL 2 is a recommendation.

-Alan

> Similarly, why would anyone want to say ďthe weight of individual  
> i1 is +infĒ? I havenít seen a single such ontology. Hence, Iíd just  
> ditch these constants and simplify our task. Iím willing to  
> personally pay 1000 bucks to anyone who runs into practical  
> problems because of that.
>
> Regards,
>
>             Boris
>
> From: public-owl-wg-request@w3.org [mailto:public-owl-wg- 
> request@w3.org] On Behalf Of Alan Ruttenberg
> Sent: 01 July 2008 18:52
> To: Boris Motik
> Cc: 'Michael Smith'; 'OWL Working Group WG'
> Subject: Re: ISSUE-126 (Revisit Datatypes): A proposal for resolution
>
> On Jul 1, 2008, at 1:32 PM, Boris Motik wrote:
>
>
> If we absolutely need +inf, -inf, and NaN, then I'd say we need to  
> add them to owl:real, and then make all other numeric datatypes  
> subsets of that datatype.
>
> Yes, I was going to suggest that. Since it's ours to define anyways.
>
>
> Finally, do we really care about +inf, -inf, and NaN? XML Schema  
> might care, but again, XML Schema is a schema and not an ontology  
> language. XML Schema does not need to do any reasoning on the  
> datatypes; it only needs to perform straightforward validation.  
> This is why I suggested to change xsd:float: we probably don't want  
> to reason about the properties of floating point arithmetic. We can  
> keep the name to make people happy. People will be able to put  
> values into their ontology that can be written in the form of  
> floats and will be perfectly happy with that; for the most part,  
> they won't be able to detect the difference.
>
> The issue is how easy or hard it is to carry data around in an OWL  
> file. If you have some quantity of data and you put it in OWL and  
> the 3 NaN that are in it make the system not able to proceed  
> because there is a syntax error, and you have to stop and figure  
> out some ugly workaround,then this is a problem.
>
> It's a little like annotations. They don't have the usual logical  
> semantics, we don't do reasoning on them, but they are important,  
> nonetheless.
>
> I realize that these complicate the reasoning a bit. For one thing,  
> its not clear to me whether we can still say that xsd:float is a  
> bounded subset of the reals, because of the INFs.
>
> -Alan
Received on Tuesday, 1 July 2008 18:57:38 UTC

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